Complete Right Heart Flow Reversal

Abstract

Although the pathophysiologic mechanism of twin-twin transfusion syndrome (TTTS) remains incompletely understood, the process appears to involve abnormal vascular communications within the placenta, leading to characteristic hemodynamic changes in the recipient fetus. The recipient twin may have progressive volume and pressure overload, congestive heart failure, and hydrops. Recipient twin echocardiographic findings, which typically include valvar regurgitation/stenosis, ventricular hypertrophy, and diastolic/systolic dysfunction, tend to occur predominantly in the right heart, with relative sparing of the left. We describe a case of complete right heart flow reversal and preserved left ventricle (LV) function in a recipient twin, with complete resolution and normalization 1 month after successful selective fetoscopic laser photocoagulation (SFLP) of communicating vessels. We suggest that the circular shunt seen preoperatively through the right heart of the recipient twin represents a pathognomonic finding for TTTS. We speculate that the right ventricle (RV) may be particularly sensitive to the increase in afterload encountered by recipient twins in TTTS.